Q 1: Is the “One Rule” of West and Popcak approved by the Church?
No. It is condemned by the Church.

In 1951, in his Address to Midwives, Pope Pius XII rejected a certain idea about marital sexual ethics. The very same idea today is called the “One Rule” by Gregory Popcak, and it is called “the one sure, objective criteria” by Christopher West. The idea is that, if a married couple perform one natural marital act open to life, everything else they do in the marital bedroom is justified by being done in the context of that act. What does Pope Pius XII say about this idea? He rejects it.

“This anti-Christian hedonism too often is not ashamed to elevate itself to a doctrine, inculcating the ardent desire to make always more intense the pleasure, in the preparation and in the performance of the conjugal union, as if in matrimonial relations the whole moral law were reduced to the normal performance of the act itself, and as if all the rest, in whatever way it is done, were justified by the expression of mutual affection, were sanctified by the Sacrament of Matrimony, and made worthy of praise and reward before God and conscience. There is no thought at all of the dignity of man and of the Christian — a dignity which restrains the excess of sensuality.” [Address to Midwives 68]

The holy Pontiff condemns the idea that, “in matrimonial relations”, the whole moral law can be “reduced to the normal performance of the act itself” (i.e. the natural marital act) and “all the rest, in whatever way it is done” is thereby justified, including acts of foreplay (“in the preparation”). Therefore, this idea that a married couple can justify all manner of unnatural sexual acts, which are inherently non-unitive and non-procreative, by performing at least one natural marital act about the same time, is contrary to Church teaching.

This passage from Address to Midwives also condemns the idea that any act is justified, if it is used as foreplay, prior to “the normal performance of the act itself”. Pope Pius XII says that the acts done “in the preparation” are not necessary moral, merely because one normal act of conjugal union occurs about the same time. Instead, “the whole moral law” still applies in the marital bedroom. And so, each act, each deliberate knowing choice, must be moral (under the three fonts of morality) in order to be justified, even when it is used as foreplay between Christian spouses. Foreplay is not automatically moral.

The idea now called the “One Rule” is condemned by Pius XII as a type of “anti-Christian hedonism” which has elevated itself to a false doctrine. He sees this idea as encouraging an “excess of sensuality” and as ignoring “the dignity of man and of the Christian”.

And yet, even today, many Catholics loudly proclaiming the lie that this “One Rule” is Church teaching. They teach the false doctrine that, as long as spouses perform one natural marital act, all the rest, in whatever way it is done, is justified. And when they are informed that the Church actually condemns this idea, they do not care. They continue to make this false claim. Therefore, it is truly a lie, and not merely an error stated in ignorance. Some of these false teachers know what the Church actually says, and they tell others the contrary anyway.